This invention relates to a cylinder head cooling arrangement for multiple valve engines and more particularly to an improved arrangement for cooling the combustion chamber of a multiple valve, single overhead camshaft internal combustion engine.
As is well known, there is a trend in internal combustion engines, particularly those employed for powering motor vehicles, to increase the performance of the engine through the use of multiple valves. Although multiple valve engines have the ability to significantly increase the performance of the engine for a given displacement, there are numerous problems to be solved in connection with the use of multiple valve engines. For example, when plural intake and exhaust valves are employed in an overhead valve engine, the area of the engine which is available to provide cooling for the combustion chamber, particularly on the cylinder head side, is significantly diminished. It is, of course, extremely important to control the cooling of the cylinder head so as to prevent unduly high temperatures which can give rise to numerous and well known defects. Furthermore, in addition to the problem of providing adequate cooling volume, it is also desirable to insure an appropriate coolant flow through the cylinder head so as to insure that cylinder head temperatures will be more uniform, particularly across the combustion chamber, so as to avoid hot spots and the disadvantages attendant thereto.
It is, therefore, a principal object of this invention to provide an improved cooling arrangement for the cylinder head of a multiple valve internal combustion engine.
It is further object of this invention to provide an improved cylinder head cooling arrangement for high performance multiple valve engines and an arrangement for insuring the proper coolant flow through the cylinder head cooling jacket.
In conjunction with the use of multiple valve engines, it is desirable if the number of camshafts required to operate the multiple valves can be reduced. This is, it is desirable to provide a relatively simple construction for operating all of the valves of a multiple valve engine. However, as the number of camshafts is reduced, the configuration of the cylinder head also becomes a problem. That is, the position of a single camshaft for operating all of the valves can give rise to certain difficulties in location of the spark plug. Basically, it is desirable to place the spark plug or spark plugs at substantially central locations in the combustion chambers so that the flame travel can be complete to all parts of the combustion chamber. However, with such spark plug and camshaft positioning, the problems of the provision of adequate cooling for the cylinder head become magnified.
It is, therefore, a still further object of this invention to provide an improved cylinder head arrangement for a multiple valve engine embodying a single overhead camshaft and having an effective cooling arrangement for the combustion chamber.